We make 10 of thousands of tight tolerance plano-plano windows that are used for Dewars.
FLIR (Forward-Looking Infrared):
Novotech manufactures high durability FLIR windows in different sizes and configurations.
These windows are abrasion-resistant and infrared transmitting.
These windows can be produced as standalone items or they can be mounted in frames. EMI shielding and/or heated windows are also options.